DIFFERENCES IN FATIGUE BEHAVIOR OF SINGLE COPPER CRYSTALS AND POLYCRYSTALLINE COPPER AT ELEVATED TEMPERATURES,
Abstract
A comparison is made of the microstructural changes occurring in annealed polycrystalline copper and in single copper-crystals when subjected similarly to fatigue deformation by alternating torsion at temperatures ranging from room temperature to 400C. The amplitudes of cyclic strain in each case were purposely chosen to be typical of those which at room temperature produce fatigue damage by the concentrating of slip in bands which finally turn into slip-zone microcracks. It is shown that this slip concentration in polycrystalline copper no longer occurs as the test temperature is raised and that fatigue damage instead concentrates at grain boundaries. Also the slip concentration ceases in single-crystal copper as the test temperature is raised but in this case, where there are no grain boundaries, the metal recrystallizes and becomes polycrystalline before fracture. It is shown further that whereas the fatigue life of polycrystalline copper decreases with increasing temperature that of the single-crystal copper remains unaltered. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1965
- Accession Number
- AD0612713
Entities
People
- H. D. Nine
- W. A. Wood
Organizations
- Columbia University